nano: follow git-for-windows and paint interface elements

[luau-project]

Description

As the title says: follow git-for-windows and paint interface elements of nano

https://github.com/git-for-windows/git-sdk-64/blob/869fd0088bed870075a3a8e109367c0920625b57/etc/nanorc#L219-L233

Note

I did not use the same colors as git-for-windows to differentiate the MSYS2 shells. The titlecolor was set as magenta (resembles MSYS2 icon color), and orange / yellow on other parts to resemble the recommended environment (UCRT64) icon color.

Screenshots

Once this PR is merged, a file opened on nano through any MSYS2 shell would look like the following image

Wishes

In my opinion, MSYS2 should go even further enabling the default syntax highlighting files by uncommenting the line 252

[Biswa96]

Software distributions should not modify user configured options except when it causes issue with the basic use case.

[luau-project]

Software distributions should not modify user configured options except when it causes issue with the basic use case.

The proposed changes do not modify any user configured options. As far as I know, user configured options for nano goes on ~/.nanorc. Any option set on ~/.nanorc will take precedence over the default settings on /etc/nanorc.